Rivet operable by means of hammer blows



y 15, 1945' x E. A. MILLER 1 2,376,072

RIVET OPERABLE BY MEANS OF HAMMER BLOWS Filed April 21, 1943 EDW-l N ALIGLIET MILLER M Patented May 15, 1945 UNITED STATES PATENT. OFFICE 'RIVET OPERABLE BY MEANS OF HAMMER BLOWS Edwin August Miller, Fairfield, Conn.

Application April 21, 1943, Serial'No. 483,846

1 Claim.

Figure 1 illustrates an upright view of an improved tubular rivet in cross-section; .Figure 2 illustrates in cross-section the same rivet, but operated to up-set relation to work-pieces; Figure 3 illustrates in cross-section the improved rivet of solid material; and the Figure 4 illustrates in cross-section the improved rivet of which the free end -has an angular contour.

With a more particular reference to the accompanying drawing, the rivets there illustrated are identical in that each embodies the improved contour of the free end susceptible to hammer blows the force of which, while manually directed axially, is diverted laterally inward and then laterally outward after the inwardly expenditure of force there provides a density of interior molecules at places where the structure thus hardened is adapted to resist and divert continued force of hammer blows in the opposite directionlaterally outward.

The numeral I designates the shank of a rivet having the usual shouldered head 2.- In the conwardly, in the first instance, the thinning metal to an up-setting degree. Contrary to such wellknown structure, the improved rivet, while main taining an outside diameter at the free end 3 substantially equal to that of the shank I, terminates at the free end 3 in a preformed convex contour having a laterally inward deflected outline. a

In the instance of a tubular structure, as illustrated by the Figures 1 and 2, this laterally inward deflected contour may take the form of either a globular terminal 3', illustrated by the Figure l, or an angular terminal 3" as illustrated by the Figure 4.

In the tubular structure of the Figure 1, the laterally inward deflected contour greatly reduces the inside diameter of the tubular passage 4 at the extreme free end, as at 5, such reduction in diameter resulting in an initially increased density of the molecules surrounding the passage III In the instance of the solid structure, the contour of the improved preformed free end 3" may take its outline from that illustrated by the Figure 1, as illustrated by the Figure 3, or may take its outline from that illustrated by the Figure 4, or of any intermediate outline.

In the Figure 1, in which the preformed end 3 assumes the form of a globular terminal 3", such form naturally includes at its base a groove 6 as a means of merging the globular terminal 3 and the cylindrical shank I, the diameters of which being substantially equal. While such a groove 6 is incidental in providing the shank I with the globular terminal 3 yet, it is to understood that, if desired, the angular preformed terminal 3", illustrated by the Figure 4, may be provided with such a groove; for while such a groove 6 is not deemed essential as an element of said improvement, it is a great aid in the mushrooming operation, as will hereinafter be explained.

In the preforming of the free ends 3 of the shank I, as illustrated by Figures 1, 3 and 4, such formation is preferably accomplished by external pressure, especially with regard to those of the Figures 1 and 4 wherein the stock of the metal walls are not thereby impaired but, if desired, in the preformed free end 3, illustrated by the Figure 3, the metal might be cut away. The impressed method, however, has its advantage, even in connection with a solid structure, in that thereby the molecules are initially made more dense, previous to hammer blows, at places where resistance to the force of hammer blows is later required in the final mushrooming operation.

It has been found by experiment, that the length of the shank portion I, exclusive of the preformed free end 3, should be substantially equal to the aggregate thickness of the bored work-pieces 1 to be assembled, and that the length of the preformed free end 3 should be approximately equal to its diameter.

In use, the improved rivet is inserted within the bore 8 of the workpieces I to be thereby assembled, the preformed free end 3 projecting therefrom free from lateral support of the wall of the bore 8. With the shouldered head 2 properly supported against the surface 9 of one of the work-pieces I, the force of hammer blows directed axially upon the preformed free end 3 will be diverted laterally inward by reason of the laterally inward deflected contour, thereby further increasing the density of the molecules. By reason of the resistance of the hardened condition of such increased density, the force of continued hammer blows will be diverted laterally outward with the result that through the lack of lateral support by the wall of the bore 8, the preformed free end 3 of the improved rivet will yield laterally outward as the preformed free end 3 is made to mushroom down upon the surface H! of the other of the said work-pieces I, thus providing for the free end 3 a permanently up-set terminal of wide area opposing the shouldered head 2 of the improved rivet, as illustrated by the Figure 2.

The mushrooming operation in each of the preformed free ends 3, illustrated by the Figures 1,

3 and 4, are substantially identical, but where of the shank I with a preformed free end, both of which free ends being made operable by force of hammer blows as hereinbefore described.

I claim:

A rivet for assembling work-pieces the free end of which rivet is operable by means of hammer blows or similar force, said rivet comprising a shank provided at one end of its axis with a shoulder means and at the opposite end with a globular-shaped terminal having a midway diameter transverse to said axis and substantially equal to that of the shank and a lesser diameter where merging therewith, the globular contour being interrupted by a circular flat top the circumference of which closely surrounds said axis and thus, upon axially directed hammer blows, made susceptible to yield, to a laterally inward I contraction to a degree of increased density of It is understood, of course, that if desired the improved rivet, instead of having the well-known shouldered head 2, may be provided at each end material thereby diverting laterally outward further axially directed blows to expand said terminal at said midway diameter and to facilitate the mushrooming of said terminal down upon the surface of one of said work-pieces.

EDWIN AUGUST MILLER. 

